1. Field of the Invention
This invention relates to a lead frame, a manufacturing method of the lead frame, and a semiconductor device that is packaged by using the lead frame.
2. Description of the Related Art
The development of a technology of a semiconductor integrated circuit has heightened a request for high-density mounting especially by using multiple pins. In response to such a request, various packaging forms have been developed for semiconductor devices.
There is a resin sealed package of a lead frame type as one of the packaging forms of the semiconductor devices. The resin sealed package has been widely used because of an inexpensive material and a shape that is suited to mass production.
In the package of the lead frame type, a semiconductor element and an inner lead portion of the lead frame are generally connected to each other through a metal wire (e.g., see Patent Document 1 as identified below).
A constitutional example of a conventional semiconductor device sealed by a resin sealed package 142 of a lead frame type will now be described with reference to FIG. 11. Two semiconductor elements 143a and 143b are mounted in the resin sealed package 142. One semiconductor element 143a is stuck to an upper surface of a dye stage 144 by a semiconductor element adhesive 145. An upper surface of the semiconductor element 143a is a circuit formation surface, and one end of a metal wire 149 is attached to a bonding electrode 150 on the circuit formation surface. Further, the other end of the metal wire 149 is connected to an inner lead portion of a lead frame 148.
An upper surface of the other semiconductor element 143b is a circuit formation surface, and one end of a tab lead 146 is attached to a bump 152 on the circuit formation surface. Further, the other end of the tab lead 146 is connected to the inner lead portion of the lead frame 148. The semiconductor element 143b to which the tab lead 146 is attached is disposed below the dye stage 144 through an insulating material 147.
If a metal wire is used for a connection between a semiconductor element and an inner lead portion of a lead frame, there is a possibility that wire cutting or the like will occur due to vibration or the like during package manufacturing. However, if a semiconductor chip and the inner lead portion are connected by flip chip bonding, the metal wire and a tab lead are made unnecessary. Thus, a possibility of metal wire cutting or the like can be eliminated, and the number of components can be reduced.
Patent Document 1: Japanese Patent Application Laid-Open No. 7 (1995)-30051 (claim 1 and FIG. 1)